This invention relates to a matrix circuit for cyclically driving in an electrostatic recording device a sequence of control electrodes, two at each instant.
An electrostatic recording device comprises a multiplicity of aligned stylus electrodes and a conductive member along the stylus electrodes to record an electrostatic image on a recording medium placed in an electrostatic field formed between the stylus electrodes and the conductive member. Usually, the conductive member is divided into a sequence of control electrodes. In order to cyclically drive the control electrodes at successive time slots, two consecutive ones in the sequence at each time slot, use is made of a matrix circuit to which this invention is applicable.
A matrix circuit generally comprises a plurality of matrix conductors, namely, a plurality of row conductors and a plurality of column conductors crossing the row conductors without ohmic contact therewith to form a matrix or cross points, and a plurality of cross-point elements adjacent the respective cross points. For use in an electrostatic recording device comprising a sequence of control electrodes, the cross-point elements are assigned to the control electrodes in one-to-one correspondence. Only two of the cross-point elements are selected at each time slot to drive the two consecutive control electrodes. It is, however, inevitable with a conventional matrix circuit for general purposes that spurious cross-point elements in excess of two are undesiredly selected at a certain time slot as will later be described with reference to one of several figures of the accompanying drawing. Another conventional matrix circuit proposed specifically for an electrostatic recording device being dealt with is capable of avoiding the spurious selection. The proposed matrix circuit, however, is complicated in structure as will also be described hereunder with reference to another figure of the accompanying drawing. The operation is also complicated particularly when one of the two consecutive control electrodes that next follows in the sequence the other has to be continuously driven at the next succeeding time slot together with another of the control electrodes that next follows in the sequence the said one control electrode.